Pulverulent material conveying apparatus

ABSTRACT

A pulverulent material conveying apparatus which includes a hollow barrel having an inlet which is adapted to be connected to a source of pulverulent material and an outlet for discharging material into a manifold chamber. A screw conveyor is rotatably mounted in the barrel for advancing the material through the barrel. Each end of the screw is mounted in bearings. The end of the screw near the outlet of the barrel is tapered so that the pulverulent material is compressed to form a fluid seal at the outlet of the barrel. A check valve is slideably mounted on the screw shaft to restrict the flow of material from the barrel into the manifold chamber. Air under pressure is supplied to the manifold chamber where it aerates the pulverulent material and entrains the material to the outlet of the manifold chamber and the conveying line. The outlet of the manifold chamber is coaxial with the barrel, and the air under pressure is supplied to the manifold chamber so that a substantially complete circle of air under pressure is formed around the outlet of the barrel.

United States Patent Boyhont et al. A

n51 3,704,917 [451 Dec.5, 1972 [s41 PULVERULENT MATERIAL CONVEYINGAPPARATUS [72] Inventors: Donald S. Boyhont, Nazareth; Marvyn L.Souders, Allentown, both of [73] Assignee: Fuller Company [22] Filed:Oct. 14, 1970 [21] Appl. No.: 80,727

FOREIGN PATENTS OR APPLICATIONS 524,415 4/1931 Germany .L ..302/s0Primary ExaminerEvon C. Blunlc Assistant Examiner-W. Scott CarsonAttorney-Jack L. Pratherand Frank H. Thomson [57] ABSTRACT A pulverulentmaterial conveying apparatus which includes a hollow barrel having aninlet which is adapted to be connected to a source of pulverulentmaterial and an outlet for discharging material into a manifold chamber.A screw conveyor is rotatably mounted in the barrel for advancing thematerial through the barrel. Each end of the screw is mounted inbearings. The end of the screw near the outlet of the barrel is taperedso that the pulverulent material is compressed to form a fluid seal atthe outlet of the barrel. A check valve is slideably mounted on thescrew shaft to restrict the flow of material from the barrel into themanifold chamber. Air under pressure is supplied to the manifold chamberwhere it aerates the pulverulent material and entrains the material tothe outlet of the manifold chamber and the conveying line. The outlet ofthe manifold chamber is coaxial with the barrel, and the air underpressure is supplied to the manifold chamber so that a substantiallycomplete circle of air under pressure is formed around the outlet of thebarrel.

8 Claims, 3 Drawing Figures PATENIEDMc 5l972 3.704.917

SHEET 1 UF 2 INVENTORS DONALD S. BOYHONT/fi MARVYN L. SOUDERS iii;

ATTORNEY PATENTED 5 I97? 3. 704 9 l 7 sum 2 OF 2 INVENTORS DONALD S.BOYHONT 8\ MARVYN L. SOUDERS BY jaw ATTORNEY BACKGROUND OF THE INVENTIONThis invention relates to pulverulent material conveying apparatus andin particular to an improved pneumatic conveying apparatus of the typeshown in US. Pat. No. 1,553,539. l

The type of pulverulent material conveying apparatus to which thepresent invention relates is generally known in the prior art and hasbeen a successful pulverulentmaterial conveying apparatus for manyyears. In such apparatus, pulverulent material to be conveyed isadvanced by means of a screw feeder from a source of material through abarrel to a wind box. Air under pressure is continuously supplied to thewind box to aerate and entrainthe pulverulent material through aconveying line which is flow connected with the wind box. The screw andbarrel aredesigned so that the material is compressed to thereby'form amaterial seal which prevents the air under pressure from backing upthrough the barrel.

It has become common practice to support the screw for conveyingthematerialthrough the pumping apparatus only at the drive motor end of thescrew and rely on the pulverulent material between the screw and thebarrel to form a bearing for supporting the other end of the screw. Suchan arrangement is satisfactory so long. as the pump screw is properlyaligned and balanced and the apparatus is working at or near capacity.In the event the apparatus is not operated under these idealconditions,this bearing may not be formed.- If the screw is 'not properly balancedand aligned in the barrel, the screw willtend to wobble in the barrel.This wobble can cause chips to break off the screw flight which causethe screw to become further out of balance and result in an increase inthe wobble. Eventually, the screw will destroy itself. When apparatus ofthe type to which the present invention relates wasoriginallyintroduced, the screw shaft was supported at both ends bymeans of suitable bearings. The arrangements of the early apparatus ofthis type had the disadvantage that when the pump was operating at lessthan capacity, a material seal was not always formed in the barrel. Thematerial seal at the discharge end of the barrel is essential for properoperation of the apparatus. In order to overcome this, a check valve wasmounted at the discharge end of the barrel. This resulted in theelimination of the bearing at the discharge end of the screw. a

An additional problem with priorapparatus of this type is that theconveying line to which material is supplied is usually offset from theoutlet of the barrel. This is a result of the check valve arrangementused in prior apparatus. With the check valve arrangement used in priorapparatus, when the pulverulent material is discharged from the barrel,it will drop toward the bottom of the wind box, and the compressed airis supplied to the wind box primarily at the bottom of the wind box.Such an arrangement has the disadvantage that it does not utilize theflow pattern of the material leaving the barrel.

SUMMARY It is, therefore, the principal object of this invention toprovide a pneumatic conveying apparatus for pulverulent materials of thetype wherein a screw conveyor feeds material into a wind box whichovercomes the disadvantages of prior apparatus of this type.

It is a further object of this invention to provide a more efficientpulverulent material conveying apparatus of the type which employs ascrew conveyor for feeding pulverulent material into a wind box whereinthe apparatus is capable of operating at both full capacity and partialcapacity without interfering with the operation of the device.

In general, the foregoing and other objects will be carried out byproviding apparatus for conveying pulverulent material comprising: ahollow barrel having an inlet for material to be conveyed-and an outlet;screw means rotatably mounted in said barrel for advancing materialthrough said barrel from the inlet to the outlet and defining with saidbarrel means for compacting the material; bearing means. for rotatablysupporting said screw means; manifold means at the outlet of said barrelfor receiving material from said barrel and having an outlet coaxiallyaligned with the outlet of said barrel and adapted to be connected to amaterial conveying line; means for supplying gaseous fluid underpressure to said manifold means for aerating said material andentraining said material through a the outlet of the manifold means;said barrel extending into said manifold means and said means forsupplying a gaseous fluid under pressure to said manifold means beinglocated upstream of the outlet of the barrel so that a flow of gaseousfluid under pressure substantially completely surrounds the outlet ofthe barrel; and check valve means slideably mounted on said screw meansfor restricting the flow of material from the outlet of the barrel intosaid manifold means.

BRIEF DESCRIPTION 0F THE DRAWINGS The invention will be described inconnection with the annexed drawings wherein:

FIG. 1 is a sectionalview of the conveying apparatus of the presentinvention;

FIG. 2 is asectional view taken on the line 22 of FIG. 1; and a v l FIG.3 is a sectional view taken on the line 3-3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The pulverulent materialconveying apparatus of the present invention includes a hopper sectiongenerally indicated at l which is suitably mounted on a base 2 andincludes an inlet portion 3 adapted to be connected to a source ofpulverulent material. The hopper section 1 is provided with a flangedopening 5 for receiving a barrel section 8. The hollow barrel section 8has an inlet 10 communicating with the hopper 1 and an outlet 12. Thebarrel 8 may be providled with a hardened metal liner 14 held in placeby means of a plate 16 and fasteners 17.

The forward or outlet end of the: barrel 8 extends into a manifoldchamber generally indicated at 20. The manifold chamber comprises ashell 21 having a coni cal portion 22 secured thereto. The shell 21 issecured to the base 2 by means ofsuitable support structure 23. Themanifold chamber 20 is closed at its rearward end by means of an annularplate 24 which is secured to the shell 21 by means of a flange 30 andsuitable fasteners. The chamber 20 has an outlet 26 at its forward endadapted to be connected to a conveying line 28. The outlet 26 of themanifold chamber is axially aligned with the outlet 12 of the barrel 8.

A screw means 35 including a shaft 36 and a helical flight 37 isrotatably mounted in the barrel 8. The end of the screw means 35 nearthe outlet 12 of the barrel 8 includes an outwardly tapered shaftportion 39 and an extension 40. The hopper section 1' is provided withbearing means 42 for rotatably supporting one end of the shaft 36. Asecond bearing 44 is mounted in the manifold chamber 20 by means of aspider 48 for rotatably supporting the forward end of the screw means35. The bearings 42 and 44 insure that the screw means is properlyaligned in the barrel 8. The rearward end of the shaft 36 is adapted tobe connected to a source of rotary motion such as an electric motor.

The manifold chamber 20 is supplied with gaseous fluid such as air underpressure from a source (not shown) through an inlet conduit 50. When airenters the manifold 35 through conduit 50, it flows into an annularchamber 52 defined by the shell 21, barrel 8, endwall 24 and a spider54. The annular chamber 52 is located upstream of the outlet 12 of thebarrel so that as the air flows toward the outlet 26 of the manifold,the air completely surrounds the discharge 12 of the barrel 8.

A check valve means 60 is slideably mounted on a sleeve 62 whichsurrounds the shaft extension 40 of the screw means'35. The check valveincludes a valve plate 64 which is biased towards the discharge 12 ofthe barrel 8 by means ofa spring 66.

A conduit 70 is provided for supplying purge air to the bearing 44 andcheck valve means 60 for keeping pulverulent material away from thesevital parts. A plate 72 is secured to the forward end of the bearing toprevent material from entering the bearing. A conduit 73 may be providedfor supplying lubricant to the bearing 44.

. In operation, material to be conveyed is supplied to the hopper 3. Asthe screw 35 rotates, the material is advanced from the hopper 3 throughthe barrel 8 to the discharge 12. The tapered portion 39 of the shaft 36plus the constant diameter barrel 8 serve to compress the material inthe barrel 8 to provide a material seal at the discharge 12 of thebarrel which prevents air from leaving the manifold 20 and backing intothe barrel 8 and hopper 3.

As the material moves through the barrel, it moves check valve 60 awayfrom the discharge 12 against the biasing force of spring 66 and thematerial enters the manifold chamber 20. Air under pressure from conduit50 is supplied to the manifold chamber by way of annular passage 52 andflows toward the outlet 26 so that it completely surrounds thepulverulent material exiting from the barrel 8. The material is aeratedand entrained past the spider 48 and into the conveying line 28.

Because the air under pressure completely surrounds the discharge 12 ofbarrel 8 and the conveying line 28 axially aligned with the discharge ofthe'barrel 8, a more efficient conveying apparatus is provided. Thematerial does not tend to fall to the bottom ofv the manifold 20 whereit would have to be picked up by the entraining air. The flow pattern ofthe material leaving the barrel 8 is utilized in conveying the material.The particular check valve arrangement used does not interfere with thisflow pattern. The bearings 42 and 44 permit the apparatus to be operatedat less than full capacity without resulting in self-destruction of thescrew means 35. The material is not relied on to form-a bearing. I

It should be apparent that the objects of this invention have beencarried out. It is intended that the foregoing be merely a descriptionof the preferred form of the invention but that the invention be limitedsolely by that in the appended claims.

lclaim:

1. Apparatus for conveying pulverulent material comprising: 7 A

a hollow barrel having an inlet for material to be conveyed and anoutlet;

screw means rotatably mounted in said barrel for advancing material fromthe inlet to the outlet and defining with said barrel, means forcompacting the material;

a pair of bearing means each mounted at one end of said screw means forrotatably supporting said screw means;

manifold means at the outlet of said barrel for receiving material fromthe barrel and having an outlet adapted to be connected to a materialconveying line;

means for supplying gaseous fluid under pressure to said manifold meansfor aerating the material and entraining the material through the outletof the manifold means; and

check valve means slideably mounted on said screw means and biasedtoward the outlet of said barrel for restricting the flow of materialfrom the outlet of the barrel into said manifold means;

one of said bearing means being mounted within said manifold means,downstream of the outlet of the barrel and upstream of the manifoldoutlet;

said check valve means being mounted between the barrel outlet and thebearing mounted within the manifold;

said means for supplying gaseous fluid being connected to said manifoldmeans upstream of the bearing means mounted within the manifold.

2. The conveying apparatus of claim 1, wherein said manifold means iscoaxially aligned with the outlet of said barrel and said means forsupplying gaseous fluid to said manifold means is located upstream ofthe outlet of the barrel so that a flow of gaseous fluid substantiallycompletely surrounds the outlet of the barrel.

3. The conveying apparatus of claim 1, wherein said barrel issubstantially cylindrical and said screw means includes a shaft having ahelical flight of substantially constant pitch and a portion near theoutlet of the barrel tapered outwardly toward said barrel to define saidmeans for compacting the material.

4. The conveying apparatus of claim 1, wherein a spider supports saidbearing which is mounted within the manifold means and furthercomprising means for supplying a gaseous fluid under pressure to saidmanifold means for cleaning said check valve means.

5. Apparatus for conveying pulverulent material comprising:

a casing defining a manifold chamber having an outlet at one end thereofadapted to have a conveying line connected thereto;

barrel means extending into the other end of said casing and having aninlet for material to be conveyed and an outlet for discharging thematerial into the manifold chamber;

screw means rotatably mounted in said barrel and having a portion nearthe outlet of the barrel for compacting the material to thereby form amaterial seal;

a pair of bearing means, each rotatably supporting one end of said screwmeans with one of said bearing means being mounted by means of a spiderin said manifold chamber;

means for supplying gaseous fluid under pressure to said manifoldchamber upstream of the bearing means which is mounted in the manifoldchamber for aerating the material and entraining the material to theoutlet of the manifold chamber;

check valve means mounted within said manifold chamber upstream of thebearing means mounted within the manifold chamber for restricting theflow of material from said barrel into said manifold chamber; and

means for supplying gaseous fluid under pressure to said bearing meansmounted within said manifold chamber and said check valve.

6. The apparatus of claim 5, wherein said check valve means is slideablymounted on said screw means and is spring biased closed against theoutlet of the barrel.

7. The conveying apparatus of claim 5, wherein said fluid supply meansis connected to said manifold chamber upstream of the outlet of thebarrel and said manifold chamber is dimensioned so that the flow ofgaseous fluid substantially completely encircles the outlet of thebarrel.

8. The apparatus of claim 7, wherein said screw means includes a shafthaving a helical flight of substantially constant pitch and an outwardlytapered portion near the outlet of said barrel to define said means forcompacting the material.

1. Apparatus for conveying Pulverulent material comprising: a hollowbarrel having an inlet for material to be conveyed and an outlet; screwmeans rotatably mounted in said barrel for advancing material from theinlet to the outlet and defining with said barrel, means for compactingthe material; a pair of bearing means each mounted at one end of saidscrew means for rotatably supporting said screw means; manifold means atthe outlet of said barrel for receiving material from the barrel andhaving an outlet adapted to be connected to a material conveying line;means for supplying gaseous fluid under pressure to said manifold meansfor aerating the material and entraining the material through the outletof the manifold means; and check valve means slideably mounted on saidscrew means and biased toward the outlet of said barrel for restrictingthe flow of material from the outlet of the barrel into said manifoldmeans; one of said bearing means being mounted within said manifoldmeans, downstream of the outlet of the barrel and upstream of themanifold outlet; said check valve means being mounted between the barreloutlet and the bearing mounted within the manifold; said means forsupplying gaseous fluid being connected to said manifold means upstreamof the bearing means mounted within the manifold.
 2. The conveyingapparatus of claim 1, wherein said manifold means is coaxially alignedwith the outlet of said barrel and said means for supplying gaseousfluid to said manifold means is located upstream of the outlet of thebarrel so that a flow of gaseous fluid substantially completelysurrounds the outlet of the barrel.
 3. The conveying apparatus of claim1, wherein said barrel is substantially cylindrical and said screw meansincludes a shaft having a helical flight of substantially constant pitchand a portion near the outlet of the barrel tapered outwardly towardsaid barrel to define said means for compacting the material.
 4. Theconveying apparatus of claim 1, wherein a spider supports said bearingwhich is mounted within the manifold means and further comprising meansfor supplying a gaseous fluid under pressure to said manifold means forcleaning said check valve means.
 5. Apparatus for conveying pulverulentmaterial comprising: a casing defining a manifold chamber having anoutlet at one end thereof adapted to have a conveying line connectedthereto; barrel means extending into the other end of said casing andhaving an inlet for material to be conveyed and an outlet fordischarging the material into the manifold chamber; screw meansrotatably mounted in said barrel and having a portion near the outlet ofthe barrel for compacting the material to thereby form a material seal;a pair of bearing means, each rotatably supporting one end of said screwmeans with one of said bearing means being mounted by means of a spiderin said manifold chamber; means for supplying gaseous fluid underpressure to said manifold chamber upstream of the bearing means which ismounted in the manifold chamber for aerating the material and entrainingthe material to the outlet of the manifold chamber; check valve meansmounted within said manifold chamber upstream of the bearing meansmounted within the manifold chamber for restricting the flow of materialfrom said barrel into said manifold chamber; and means for supplyinggaseous fluid under pressure to said bearing means mounted within saidmanifold chamber and said check valve.
 6. The apparatus of claim 5,wherein said check valve means is slideably mounted on said screw meansand is spring biased closed against the outlet of the barrel.
 7. Theconveying apparatus of claim 5, wherein said fluid supply means isconnected to said manifold chamber upstream of the outlet of the barreland said manifold chamber is dimensioned so that the flow of gaseousfluid substantially completely encircles the outlet of the barrel. 8.The apparatus of claim 7, wherein said screw means includes a shafthaving a helical flight of substantially constant pitch and an outwardlytapered portion near the outlet of said barrel to define said means forcompacting the material.